Abstract 1500 Understanding the role of galactose and glucose on the composition of E. coli extracellular polymeric substance and biofilm growth

We are exploring the impact of galactose and glucose on the composition of E. coli extracellular polymeric substances (EPS) and biofilm growth, and aim to identify metabolic targets associated with biofilm formation and understand how nutrient availability remodels cellular pathways, leading to diverse biofilm phenotypes. Early work from our lab showed that sugar lactose, a disaccharide composed of glucose and galactose, increases biofilm growth at warmer culture temperatures (37 °C). E. coli cultures were treated with varying concentrations of different sugars, including galactose, glucose, and glucose + galactose at several growth temperatures. Our investigation included both a rich culture media (LB) and minimal media (M9), where the added sugar was the only carbon source present. We grew biofilm on both glass wool and agar substrates and measured the amount of growth using a crystal violet assay.We analyzed the amount of total protein and carbohydrate in the EPS using biochemical assays and confocal microscopy. Our results highlight that the influence of lactose appears to be greater than the individual monosaccharides that compose it. We found that at 28 °C glucose and glucose + galactose have similar biofilm growth, and that at 37 °C galactose and glucose + galactose have similar biofilm growth. This provides us with an interesting target, lactose, to further study its uptake, metabolism, and modulation of the genes expressed in E. coli as it relates to biofilm formation. We would like to thank Oberlin College, The Research Corporation for Science Advancement, and the National Science Foundation (MCB-2226953) for their generous funding support.